Compressor



J. STUMPF.

COMPRESSOR Patented Mar. 15, 1898.

(No Model.)

Fries.

PATENT JOHN STUMPF, OF CHICAGO, ILLINOIS.

COMPRESSOR.

SPECIFICATION forming part of Letters Patent No. 600,626, dated March15, 1898. Application filed November 10,1896. Serial No. 611,591. (Nomodel.)

To aZZ whom it may concern:

Be it known that I, JOHN STUMPF, a subject of the Emperor of Germany,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Improvement in Compressors, of which thefollowing is a specification. My invention relates more particularly toimprovements in air compressors, though, generally stated, myimprovements are applicable to fluid compressing and forcing pumpsgenerally.

My object is to provide the compressor-cylinder with valves andvalve-operating means of an improved construction which renders themparticularly quick, smooth, and noiseless in action and capable of agreater lift than the valves hitherto employed in the same connection,all to the end of rendering the compressor more desirable for itspurpose.

The drawing shows a view which, in the main, is a vertical longitudinalsection of an air-compressor cylinder with my improvements applied,

A is a shell or casing formed of shell members fitted and boltedtogether. In the shell is a cylindrical piston-chamberB, having endwalls or heads B B Working in the chamber B is the piston C on a stem C,which passes through the wall 13 and through a stuffing-box t. On thewalls B B are eduction-chambers D D, opening into a common passage Dhaving an outlet 8, which-in practice will communicate with theair-discharge pipe. In each of the chambers D D is a plug or valve-shellE, each comprising a hollow body portion r, provided in its outer endwith a wall r and with a series of openings r around its circumference.The opposite or inner ends of the plugs are open and extend throughopenings in the walls B B preferably flush with the inner surfaces ofthe said walls. The Wall 1 of each plug is provided with a centralforward projecting hollow guide-sleeve r and extending through the saidwall about the guide-sleeve are one or more openings W. The outercircumference of the wall 1" of each plug is threaded to receive ascrew-cap n, which, with the adjacent wall r, forms a chamber r. Theinner end of each valve-shell or plug E affords a valveseat 0,preferably flush with the respective wall of the chamber B. In thechamber 1 of each shell or plug E is a piston q, having a central boss gon its inner face, a central opening (1 through it, and a recess g inits outer face about the opening (f. A valve 99 at each shell E isadapted to seat against the seat r and has a stem portion 19, whichworks through the guide r and is screwed at its outer end upon the bossq of the piston g, which latter thus forms a part of the valve.Extending longitudinally through each valve p and stem p is a passageopening into the passage g of the piston q. The arrangement is such thatair compressed by the piston C in the chamber B in the direction of oneof the valves 19 will pass through the hollow stem of the latter and thepassage (1 into the recessed portion g of the piston q, and as the saidrecessed face presents a greater area to the pressure than the front ofthe valve 10 the tendency will be to force the piston g away from thewall r presented by the screwcap and thus move the valve 19 from theseat a. When the piston C is moved in the direction away from one of thevalves 1), the suction of air through the valve-stem and opening q? willcause the pressure of the .air in and surrounding thevalve-shell to beexerted through the openings r and in the chamber r against the pistonq, pressing the latter to the wall r and 'thus holding the valve 19closed. Thus each of the valves 19 when opened and closed is held insuch position by pressure exerted in the direction contrary to themovement of the piston C. i

, As I prefer to construct the parts described, the piston C as it nearsthe end of its stroke in the opposite directions strikes a valve 19 andcloses it against the resistance of the airpressuie, the meeting facesof the valve and the stop or portion of the piston C which strikes thevalve being sufficiently out of conformity with each other to permit thefree escape of air from behind the piston q through the stem of thevalve. It will be seen that the lift or degree of opening of the valve19 is not affected by the sweep or traverse of the piston C, and thevalve may therefore be caused to lift and open the ports at r very wide.The air pressed from behind the piston q as the valve 19 is being closedoperates as a cushion and prevents jarring of the valve.

When a valve 10 is opened under pressure exerted from the piston 0, itsoperation, though quick, is against the back pressure of the air in thechamber rflwhich while escaping through the ports r prod uces a cushionagainst the piston q suffieient to obviate all jar of the valve inopening. The valves 19, furthermore,when opened or closed are held ineither position by air pressure with comparatively great force, thusobviating the necessity of springs, which are always undesirable. Owingto the fact that in the final movement of the main piston while closinga valve p an increased compression of the fluid between the piston andadjacent end wall is effected, particularly when running above a certainspeed, there would be danger of the valves being opened momentarily bythe back pressure in the chamber or recess g unless means are providedto prevent it. To obviate this difficulty, I provide each valve 13 witha forwardprojecting part 19 which may be tubular, as shown, and providedwith a slot or vent opening 19 In eachside of the piston O, I provide arecess 2', with a bolt or threaded pin 2" extending through the pistonat the center of the recesses and confined in place by nuts t On theouter endsof the pin 1" are stops or nuts 2' and surrounding the pin inthe recesses are loose disks or cups 11 held normally against the stopsand flush with the surfaces of the piston by means of cushioning-springsvii-confined in the recesses. In practice the parts 19* would project,say, oneeighth or one-fourth of an inch beyond the faces of the valvesp, whereby as the piston approaches one of the valves one of itscushioned disks i engages and is compressed by contact with theprojection 19 until the-piston engages the valve to close the latter. Inthe initial return movement of the piston the pressure of thecushioning-disk against the valve will tend to hold the same to its seatuntil the evacuating action of the piston has become sufficient toprevent the valve from jumping or momentarily leaving its seat. As afurther precaution against the jumping of the valves, as described, orin lieu of the cushioning devices, I provide at the top of the cylindertoward each end a by-pass 77., both ports 71 of which open to oppositesides of the piston when the latter completes its stroke in thatdirection. The by-pass effects immediate equalization of pressure onopposite sides of the piston or lowering of pressure in the clearancebetween the piston and the adjacent wall, so that before the pistonmoves away from the respective valve 19 the pres-. sure in the chamber(1 thereat will be reduced below the point where it will cause the valveto jump. I show valves 71 at the by-passes, which may be turned toregulate the sizes thereof or close them altogether, if desired.

F F are induction-valve shells, each comprising a cylindrical plugportion a, open at its inner and outer ends and passing at its inner endthrough the respective wall of the piston-chamber B and extending flushwith the inner surface of the wall. In each plug n is a series ofcircumferential openings n, com municating with the outside air, and theouter end portion is threaded to receive a screw-cap F. Each plugnpresents an inner circumferential guide-surface 92 an outlet n to thechamber B, and an annular shoulder or stop n at its outer end. In theouter face of each plug a is an annular recess 7?, communicating through'small passages a with the surrounding atmosphere. Each cap F is formedwith an enlarged part m, at which it is screwed upon the plug and whichaffords an inner annular guide-surface m, a somewhat reduced part maffording an inner circumferential guide-surface m and a central tubularextension m closed at its outer end. In each of the shells F is a hollowcylindrical valve F sliding in the guide formed by the surfaces 42 mEach valve is open at its inner end and closed by a walll at its outerend. In the wall Z of each valve F is a central guide-opening Z and one,or a series of openings or ports Z Integral with each valve F andextending around its circumference is an annular flange Z which slidesupon the guide-surface m. In each cap portion F, in the position shown,is a passage m into which projects a regulating-screw m which may beturned to regulate the size of the passage.

On each side of the piston O, in line with the ports 01 and Workingthrough the latter, are cylindrical projections O C, from which extendcentral stems O passing through the guide-openings Z in the valves F andprovided at their ends beyond said guide-openings with cushioned headsor stopsO which slide loosely in the guides formed by the tubes m Thecylindrical projections O are of a size to cause them to slide looselythrough the ports a and also loosely into the valves F The view showsthe piston O nearly, but not quite, at the limit of its movement towardthe Wall B and the valve F at the wall B open. In the movement of thepiston, wherein it closes the valve 19 at the wall E the head O on thestem 0 to the left in the figure engages the outer end of the valve Fand moves it until it seats against the port a and crosses and closesthe ports a, through which air is supplied to the chamber 13. In thereverse movement of the piston 0 toward the wall B the air as it iscompressed in the direction of said wall exerts pressure through theports Z in the valve 15 at said wall and through the port or passage magainst the flange Z of the valve, thereby holding the latter to itsseat at the shoulder a and maintaining the induction-ports it closed. Inthe initial movement of the piston O in the direction of the wall B thecylindrical projection to the right in the figure produces a suction ofair through the adjacent ports Z and passage 112 thereby withdrawingpres- IIO sure from behind the flange Z and causing the air undersurrounding atmospheric pressure to enter through the ports a and movethe said valve to the right in the figure to open the respective ports aand admit air to the chamber B on the side B thereof. The valves F areheld open and closed by fluid-pressure exerted in the direction contraryto the direction of movement of the piston O, and they open, asdescribed, simultaneously with the initial movement of the vpiston inthe direction away from them. As before stated, the valves F are heldclosed by the pressure of air passing through the passages m and bymeans of the screws m these passages may be so regulated as to size thatwhile they permit the valves to be closed with all necessary quicknessby the yielding stops 0 the closing is effected against a slight backpressure of air, which, acting counter to the yielding stops, preventsjar upon the valves. Thus the valves are closed in a manner so gentlethat their operation is practically noiseless. The withdrawal ofpressure through the passages 'm from behind the flanges I under thesuction action of the piston 0 causes the valves to open with allnecessary quickness, but noiselessly and without jar. Theinduction-valves F like the eduction-valvesp, may have any desired lift,and, being without springs, present comparatively little resistanceagainst opening and are particularly durable and desirable for theirpurpose.

WVhile I prefer that both the induction and eduction valves shall beclosed by the direct engagement therewith of the piston or a partmovable with or carried by the piston in the final movement of thepiston toward the limit of its traverse, as described, the valves may beclosed, if desired, by the fluid-pressure in the initial movement of thepiston from the limit of its traverse, so that the valves will be closedas well as maintained closed by the force of fluid-pressure broughtabout by the compression and suction actions of the piston.

My improvements may be applied with benefit to gas or other pumps orcompressors, and they may be modified in the matter of details to meetall requirements without departing from the spirit of my invention asdefined by the claims.

What I claim as new, and desire to secure by Letters Patent, is-- 1. Ina compressor, the combination with the cylinder and piston, of afluid-passage communicating with the cylinder, a valve at said passage,and means carried by the valve and operated alone by fluid-pressurebrought about by the compression and suction action of the piston formoving and holding said valve alternately both in opening and closingpositions, the pressure, in each instance, being in the directioncontrary to the movement of the piston, substantially as described.

2. In a compressor, the combination with the cylinder and piston, of afluid-passage communicating with the cylinder and a valve governing saidpassage in open communication at both its inner and outer sides with thecylinder, the outer face of the valve being of greater area than itsinner face, whereby said outer face is acted upon to press the valve toand from its seat under the compression and suction actions of thepiston, the pressure, in each instance, being in the direction contraryto the movement of the piston, which brings it about, substantially asdescribed.

3. In a compressor, the combination with the cylinder and piston, of aninwardly-lifting valve governing the cylinder dischargepassage, andmeans carried by thevalve in open communication at its outer side withthe cylinder and operated alone by fluid-pressure brought about by thecompression and suction action of the piston for moving and holding saidvalve alternately both in opening and closing positions, the pressure ineach instance, being in the direction contrary to the movement of thepiston, substantially as described.

4. In a compressor, the combination with the cylinder and piston, of anoutwardly-lifting valve governing the cylinder inductionport, and apiston carried by the valve having a greater area than the latter andhaving open communication at its outer side with the interior of thecylinder and operated alone by fluid-pressure brought about by thecompression and suction action of the piston for moving and holding saidvalve alternately both in opening and closing positions, the pressure,in each instance, being in the direction contrary to the movement of thepiston, substantially as described.

5. In a compressor, the combination with the cylinder and piston, of afluid-passage communicating with said cylinder, and a valve governingsaid passage in the path of a stop movable with the piston, whereby thevalve is closed in the movement of the piston to the end of itstraverse, the valve, at its outer side being in open communication withthe cylinder and there presenting a greater area to pressure than at itsinner side, whereby the valve when closed is maintained closed byfluid-pressure under the action of the piston, substantially asdescribed.

6. In a compressor, the combination with the cylinder and piston, of aninduction-passage communicating with the cylinder, and anoutwardly-opening valve governing said passage exposed at its outer sideto pressure from the cylinder, whereby it is opened under the suctionaction of the piston, and in the path of a stop movable with the piston,whereby in the movement of the piston to the limit of its traverse awayfrom said passage the valve is closed by the engagement with it of thestop, and in the movement of the piston toward said passage the valve ismaintained closed by the fluid-pressure generated by the piston,substantially as described.

7. In a compressor, the combination with the cylinder and piston, of aneduction-passage extending from said cylinder, and an inwardly-openingvalve governing said passage in the path of a stop movable with thepiston, and exposed at its outer face to pressure from the cylinder,whereby under the force of fluid-pressure generated by the piston thevalve is opened, and in the movement of the piston toward said passagethe valve is engaged and closed by said stop, and in the movement of thepiston away from said passage the valve is maintained closed by thesuction action of the piston, substantially as and for the purpose setforth.

8. In a compressor, the combination with the cylinder and piston, of aneduction-passage extending from said cylinder, an inwardly-opening valvegoverning said passage in the path of a stop movable with the piston andexposed at its outer face to pressure from the cylinder, whereby underthe force of fluidpressure generated by the piston the valve is opened,and in the movement of the piston toward said passage the valve isengaged and JOHN STUMPF.

In presence of M. J. FRosT, J. H. LEE.

